Treating Older Patients in Cardiogenic Shock With a Microaxial Flow Pump: Is It DANGERous?

Background: Whether age impacts the recently demonstrated survival benefit of microaxial flow pump (mAFP) treatment in patients with ST-segment elevation myocardial infarction (STEMI) and cardiogenic shock (CS) is unknown. Objectives: The purpose of this study was to assess the impact of age on mortality and complication rates in patients with STEMI-related CS randomized to standard care or mAFP on top of standard care. Methods: This is a secondary analysis of the Danish-German Cardiogenic Shock (DanGer Shock) trial, an international, multicenter, open-label trial, in which 355 adult patients with STEMI-related CS were randomized to receive an mAFP (Impella CP) plus standard care or standard care alone. The primary outcome of 180-day all-cause mortality is analyzed according to age and intervention. Results: From lowest to highest age quartile, the median ages (range) were 54 years (Q1-Q3: 31-59 years), 65 years (Q1-Q3: 60-69 years), 73 years (Q1-Q3: 70-76 years), and 81 years (Q1-Q3: 77-92 years). There were no differences in blood pressure, lactate level, left ventricular ejection fraction, or shock severity at randomization across age groups. Mortality increased from lowest to highest quartile (31%, 47%, 61%, and 73%, respectively; log-rank P < 0.001), with an adjusted OR for death at 180 days of 7.85 (95% CI: 3.37-19.2; P < 0.001) in the highest quartile compared to the lowest. The predicted risk of mortality was higher in the standard-care group until approximately 77 years, after which the predicted risk became higher in the mAFP group (P = 0.20). In patients <77 years, a reduced 180-day mortality was observed in patients randomized to the mAFP (OR: 0.45; 95% CI: 0.28-0.73; P = 0.001), opposed to patients aged ≥77 years (OR: 1.52; 95% CI: 0.57-4.08; P = 0.40), P for interaction = 0.028. Complications were more frequent in the mAFP group, but there were no apparent differences in incidence of complications across all ages. Conclusions: This exploratory secondary analysis of the DanGer Shock trial demonstrates that older patients with STEMI-related CS experience high mortality and may not attain the same benefit from routine treatment with an mAFP as younger patients. Incorporating age as a factor in patient selection may enhance the overall benefit of this therapy. (Danish Cardiogenic Shock Trial [DanShock]; NCT01633502)